There is a technology for designing circuits by using an electronic design automation (EDA) tool, such as a computer aided design (CAD) tool. For example, the EDA tool enables automatic wiring between two cells (for example, a latch, a flip-flop, and the like) that are designated to be connected. In recent years, in the physical design of a circuit, the number of cases is increasing, in which a timing problem occurs due to the presence of a bypass wiring extending in a direction opposite to a direction of approach from a cell that transmits a signal to a cell that receives the signal among wirings from the cell that transmits the signal to the cell that receives the signal. The reason why the number of the cases with the timing problem is increasing is that, in recent years, the operating frequencies of circuits have increased and the density of the circuits has increased due to the miniaturization of technologies.
In a circuit with the timing problem, operation is sometimes not performed normally. Therefore, conventionally, a wiring inspection method has been proposed to inspect whether there is a bypass wiring, in order to detect a circuit that does not operate normally. As an example of the wiring inspection method, there is a method in which a human visually inspects a circuit after wiring. As another example of the wiring inspection method, there is a method in which a computer inspects whether there is a bypass wiring based on a wiring pattern of a circuit after wiring. As for an example of the conventional techniques, see Japanese Laid-open Patent Publication No. 10-74842 and Japanese Laid-open Patent Publication No. 05-29460, for example.
However, in the wiring inspection method as described above, in some cases, inspection is sometimes not performed in a simple and easy manner. For example, in the method in which a human visually inspects a circuit after wiring, it takes a long time for a human to inspect more than thousands of wirings. Therefore, in the method in which a human visually inspects a circuit after wiring, it is difficult to perform the inspection in a simple and easy manner. Furthermore, in the method in which a computer inspects whether there is a bypass wiring based on a wiring pattern of a circuit after wiring, the same problem occurs. Specifically, in the method in which a computer inspects whether there is a bypass wiring, a wiring pattern is analyzed based on data indicating the wiring pattern, and whether there is a bypass wiring is inspected based on the analyzed wiring pattern. Therefore, it takes a long time to analyze the wiring pattern and inspect whether there is a bypass wiring based on the analyzed wiring pattern. Consequently, even in the method in which the computer inspects whether there is a bypass wiring based on a wiring pattern of a circuit after wiring, it is difficult to perform the inspection in a simple and easy manner.